If you know for sure you want to be an airline pilot, then seniority is the #1 benefit you will gain with a 2 yr head start. Like many have said, with a guard or reserve gig, you can stay current and financially solvent with the ability to be readily available the moment the airline you desire starts hiring. You have the pedigree for a mil pilot, and hopefully some contacts.

Also, in the Navy reserves as well it is easier to get a flying billet the more junior and current you are, as you ripen in your career and seniority, it gets harder to make the transition.

My understanding of the sep pay for reservists is that they take it out pro-rated interest free from your retirement pay at age 60 over a 20 year span, so $125K will reduce your reserve retirement by roughly 6K per year once you collect a reserve retirement. Not bad for an interest free loan.